Salvage radiotherapy for regional lymph node oligo-recurrence after radical surgery of non-small cell lung cancer

Background: Currently, evidence-based guidelines for salvage therapy to treat mediastinal lymph node (LN) oligo-recurrence in post-resection non-small cell lung cancer (NSCLC) are limited. In patients previously treated by surgery without irradiation, radiotherapy (RT) might be safely utilized. We evaluate the clinical outcomes of salvage RT for patients with LN oligo-recurrence that developed after radical surgery for NSCLC. Methods: Thirty-one patients with stage I–IIIA NSCLC who developed regional LN oligo-recurrence between 2008 and 2013 were reviewed. The median time from surgery to recurrence was 12 months. Fifteen patients (48.4%) had single LN recurrence. All patients were irradiated by 3-dimensional conformal RT at the recurrent LN area with daily fractions of 2–3 Gy, with a median dose of 66 Gy (range 51–66). Sixteen patients also received chemotherapy. Results: After salvage RT, 16 patients achieved a complete response, nine a partial response, and six had stable disease. The median follow-up was 14 months (range 3–76). One and two-year in-field control rates were 88.4% and 75.8%, respectively. One and two-year progression-free survival rates were 73.1% and 50.9%, respectively. Progression sites were predominantly distant. Ten of the 31 patients (32.3%) met the revised Response Evaluation Criteria for Solid Tumors for a complete response by the final follow-up. Recurrent LN size (<3 vs. ≥3 cm) was a significant prognostic factor for progression-free survival (P = 0.013). Conclusion: Salvage RT for patients with regional LN oligo-recurrence after radical surgery was an effective treatment option with an acceptable level of toxicity.